Me and Cliff out of Clearwater have been talking about that very subject. It appears the upper is 7/8 or .875 OD..... and the lower OD is .783. It may depend on the thickness of the 7/8th as to how much slack you have. Looks like 3/4 lower...... or .758 is as close as we've found right now. On the lower if you jump from a .064 to a .065 thickness...... price really seems to go up. My suggestion......... lets see what Pete @#$%& has for us. Other suggestions......was a whites tall boy doubling up on the washers........ some of us did that with the Xcals before Pete came out with a good hard head on his lower shaft.

I know I just got a message from him Cliff. He thinks this one is going to be a ground up design because of the size. Looking forward to see what he comes up with. Dang no one near Pete to help a brother out?

Nothing is standard about the Equinox. two metal shaft with one necked down to fit into one another. With both having an OD of 7/8th their is not an off the shelf cam lock to help with shaft play. The best I see for a CF shaft is a one piece from arm cuff to lower shaft.

Proprietary past is Minelab's norm.
The battery and its charging connector, new spring clips with non-standard US (SAE) hole size so the standard US spring clips will not fit the holes in the shaft. The audio connector is also proprietary. Waterproof headphone unless a third party can get the connectors. The coils? Coil bolt and wing nut? If Minelab would sell the individual parts to us, there would be many happy detectorists swinging along with their Equinox.

See the post about shaft play for a fix for the shaft play if your Equinox has rotational play between the metal shafts.

Okay, I just got home from hunting the beach with my Nox 800 and a new Plugger carbon fiber shaft. Was no problem to mount the control head on Plugger's 3/4" carbon fiber shaft even though the Nox's upper shaft is 7/8", no play or slop it clamped up just right. I also had Bill move the control head index hole 1" longer away from the arm cuff than stock due to my long forearm length. I also had the overall shaft made 1" longer than stock.

The only issues I found is the Nox's lower shaft is to big in its OD to fit inside Plugger's carbon fiber shaft's ID, so we swapped out the Nox's lower shaft and used a Whites lower shaft which will fit the Nox's coil...oh and the Nox coil and Nox lower shaft ends have larger holes than the Whites, Excal or Sov coils.
I used the plastic 1/4" bolt Bill sent, but I could have drilled the Whites lower rod's hole out to the larger Nox's coil holes without any problems and if the 1/4" plastic bolt gives me any problems I will drill and use the Nox's coil mounting bolt. You could also use a Excal or Sov lower shaft just remember the length adjustment holes are in different positions on these two shafts.

Here is the weight difference:
Stock Equinox upper, middle and lower shaft weight in at 280 grams
Plugger carbon fiber 36" shaft and Whites lower shaft weight in at 226 grams.
So the diff is just shy of 2 OZ lighter for the carbon fiber & White lower and to break it down farther my custom fit carbon fiber shaft was 131 grams and the the Whites lower shaft is 95 grams.

I am shipping the complete Nox shaft to Plugger so he can build shafts with all the adjustments to fit anyone.
I will post pic as soon as my camera's batteries get charged up.

CF is the way to go. I have two and when production starts, guess I will bite the bullet if the Equinox deserves one. Until then my plastic spring pin and electrical tape will have to do. Only problem I may have is packing the one piece shaft when traveling.
Glad all worked out for you. Bill is great to work with he has done me well with specific requests beyond the standard stock shaft he makes.